1. Field of the Invention
The present invention relates to a music search device, and more particularly to a music search device for searching for music data based on a user's subjective evaluation.
2. Description of the Background Art
In recent years, with the availability of personal computers, or the like, having a large-capacity storage device and with the advancements in the music data compression technology, a large number of music tunes (a large amount of music data) can be stored in a personal computer. Where a user can store a large number of tunes, it would be convenient for the user to be able to identify a tune of interest from among a large number of tunes by specifying an image that the user has for such a tune, as well as by specifying its title.
Music search methods for searching for a tune according to the user's impression of such a tune have been proposed in the art. In these methods, a musical characteristic quantity (such as tempo or beat) of a tune is automatically extracted from the tune data and converted into an impression quantity (such as violent-ness or refreshing-ness), which is obtained by quantifying the impression of the tune. The user, searching for a tune, inputs an impression quantity, and a tune having an impression quantity close to the inputted impression quantity is presented to the user. Thus, the user can easily find a tune of a certain image intended by the user.
The conversion between the characteristic quantity and the impression quantity can be performed by using a mapping function. The mapping function is derived from combinations of impression quantities obtained by actually evaluating various tunes, and characteristic quantities uniquely derived from the tunes. More specifically, the impression quantity and the characteristic quantity are obtained for each of a plurality of tunes, and a mapping function is derived from the obtained combinations so that the impression quantity and the characteristic quantity can be properly converted to each other by the mapping function for those tunes. Using the derived mapping function, the impression quantity of a tune that has not been actually evaluated can be calculated.
However, each person has a different perception from others. Therefore, a particular mapping function cannot produce conversion results that agree with the perceptions of all users. Moreover, people have to actually evaluate a number of tunes to obtain a mapping function. If the number of tunes evaluated or the number of people evaluating tunes is not sufficient, it may not be possible to obtain a desirable mapping function (i.e., a mapping function capable of producing conversion results that agree with the perceptions of many users). Therefore, with the conventional music search methods, the tune presented to the user in response to an impression quantity inputted by the user may not be a tune of the image intended by the user.
Moreover, with the conventional methods, the mapping function for the conversion between the characteristic quantity and the impression quantity is a predetermined fixed function. Therefore, even if the search results do not agree with the perception of the user, the user cannot make adjustments to the function. An ideal mapping function for a certain user may be obtained if the user actually evaluates a large number of tunes, but it will be quite time-consuming and tiring for the user. It is quite impractical that each user has to evaluate a large number of tunes to obtain a mapping function that suits the user. As described above, with the conventional music search methods, the search results may not agree with the perception of the user. Moreover, in such a case, the user is left with no option at all for improving the search function.